1. Technical Field
Embodiments of the present invention relate to a reaction force adjustment member and a suspension.
2. Related Art
Motorcycles have a suspension in order to improve ride comfort or the like. FIG. 11 is a side view illustrating an appearance of a related-art suspension 200 provided on a rear wheel of one of the motorcycles.
As illustrated in FIG. 11, the suspension 200 for the rear wheel includes a damper body 210 that absorbs and damps vibration transmitted from a road surface during travelling and a metal coil spring 220 that alleviates transmission of vibration to a vehicle body. The suspension 200 is provided between the vehicle body and a swing arm attached to the wheel, for example. Thus, a portion of the damper body 210 is inserted into the metal coil spring 220, and the metal coil spring 220 is provided between the vehicle body and the swing arm.
FIG. 12 is a diagram illustrating reaction force characteristics of the metal coil spring 220 of the suspension 200. FIG. 12 illustrates the reaction force characteristics of three metal coil springs 220 having different elasticity. As illustrated in FIG. 12, the reaction force characteristics of the metal coil spring 220 changes approximately in proportion to a change in a stroke of the suspension 200.
In the suspension 200, when different reaction force characteristics of the metal coil spring 220 are desired, it is necessary to replace the metal coil spring 220 itself with another metal coil spring 220.
An air spring structure which includes a diaphragm around a piston rod to constitute an air chamber and which generates reaction force using a pressure of air in the air chamber is known as an example of a suspension structure.
When a coil spring structure is compared with the air spring structure, a load of the coil spring is heavier than constituent members of the air chamber, an inertial force and a bending load acting on the suspension in the coil spring structure are larger than those of the air spring structure. Thus, the coil spring structure has poor stroke operability than the air spring structure. Thus, in order to adjust the reaction force easily and improve the stroke operability, the air spring structure is more ideal than the coil spring structure.
FIG. 13 is a diagram illustrating an example of reaction force characteristics of a suspension having the air spring structure. As illustrated in FIG. 13, the reaction force characteristics of the suspension having the air spring structure change monotonously with the change in the stroke of the suspension.